Identifying model pollutants to investigate biodegradation of hazardous XOCs in WWTPs

Xenobiotic organic compounds (XOCs) in wastewater treatment plant (WWTP) effluents might cause toxic effects in ecosystems. Several investigations have emphasized biodegradation as an important removal mechanism to reduce pollution with XOCs from WWTP effluents. The aim of the study was to design a screening tool to identify and select hazardous model pollutants for the further investigation of biodegradation in WWTPs. The screening tool consists of three criteria: The XOC is present in WWTP effluents, the XOC constitutes an intolerable risk in drinking water or the environment, and the XOC is expected to be biodegradable in WWTPs. The screening tool was tested on bisphenol A (BPA), carbamazepine (CBZ), di(2ethylhexyl)-phthalate (DEHP), 17beta-estradiol (E2), estrone (E1), 17alpha-ethinyloetradiol (EE2), ibuprofen, naproxen, nonylphenol (NP), and octylphenol (OP). BPA, DEHP, E2, E1, EE2, and NP passed all criteria in the screening tool and were selected as model pollutants. OP did not pass the filter and was rejected as model pollutant. CBZ, ibuprofen, and naproxen were not finally evaluated due to insufficient data.     

Removal of bis(2-ethylhexyl) phthalate at a sewage treatment plant

Bis(2-ethylhexyl) phthalate (DEHP) concentrations were measured at different stages in a full-scale sewage treatment plant (STP) and mass balances were calculated. The DEHP load to treatment process coming from the sewer system and the internal load comprising returned supernatants and filtrate from sludge treatment and excess secondary sludge were at the same level. The DEHP removal efficiency from the water phase at the STP was on average 94% of sewage DEHP, the main removal process being sorption to primary and secondary sludges. On average 29% of DEHP was calculated to be removed in the biological nitrifying-denitrifying activated sludge process, which was much less than expected from laboratory biodegradation studies described in literature. Monoethylhexyl phthalate, the primary biotransformation product of DEHP, was not detected at any treatment stage. Approximately 32% of DEHP in sewage was removed during anaerobic digestion of the sludge, while 32% remained in the digested and dewatered sludge.     

Degradation of phthalate esters in an activated sludge wastewater treatment plant

Efficient removal of phthalate esters (PE) in wastewater treatment plants (WWTP) is becoming an increasing priority in many countries. In this study, we examined the fate of dimethyl phthalate (DMP), dibutyl phthalate (DBP), butylbenzyl phthalate (BBP), and di-(2-ethylhexyl) phthalate (DEHP) in a full scale activated sludge WWTP with biological removal of nitrogen and phosphorus. The mean concentrations of DMP, DBP, BBP, and DEHP at the WWTP inlet were 1.9, 20.5, 37.9, and 71.9 μg/L, respectively. Less than 0.1%, 42%, 35%, and 96% of DMP, DBP, BBP, and DEHP was associated with suspended solids, respectively. The overall microbial degradation of DMP, DBP, BBP, and DEHP in the WWTP was estimated to be 93%, 91%, 90%, and 81%, respectively. Seven to nine percent of the incoming PE were recovered in the WWTP effluent. Factors affecting microbial degradation of DEHP in activated sludge were studied using [U-¹⁴C-ring] DEHP as tracer. First order rate coefficients for aerobic DEHP degradation were 1.0×10⁻², 1.4×10⁻², and 1.3×10⁻³ at 20, 32, and 43 °C, respectively. Aerobic degradation rates decreased dramatically under aerobic thermophilic conditions (<0.1×10⁻² h⁻¹ at 60 °C). The degradation rate under anoxic denitrifying conditions was 0.3×10⁻² h⁻¹, whereas the rate under alternating conditions (aerobic-anoxic) was 0.8×10⁻² h⁻¹. Aerobic DEHP degradation in activated sludge samples was stimulated 5-9 times by addition of a phthalate degrading bacterium. The phthalate degrading bacterium was isolated from activated sludge, and maintained a capacity for DEHP degradation while growing on vegetable oil. Collectively, the results of the study identified several controls of microbial PE degradation in activated sludge. These controls may be considered to enhance PE degradation in activated sludge WWTP with biological removal of nitrogen and phosphorus.     

Biosynthesis of di-(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP) from red alga--Bangia atropurpurea

The contents of di-(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP) of red alga, Bangia atropurpurea, filaments cultured in artificial sea water medium were similar to those cultured in natural sea water medium. In the culture experiment, B. atropurpurea filaments were found to synthesize de novo phthalate esters. Additionally, DEHP and DBP contents in different species of algae grown in the same environment were different significantly, suggesting that it was due to the intrinsic nature of algae.     

水源水质受DEHP污染的粉末活性炭吸附处理工艺

采用含邻苯二甲酸二(2-乙基己基)酯(DEHP)的试验水样模拟城市取水水源发生DEHP水污染事故,测定粉末活性炭(PAC)对水样中DEHP的吸附性能,考察PAC炭种、吸附时间、DEHP初始浓度和PAC投加量等因素对DEHP的吸附量和脱除率的影响。试验结果表明:木屑PAC具有较大的比表面积,对DEHP具有良好的吸附效果,适用于DEHP水污染的应急处理。应急处理一般的DEHP水污染事故,DEHP污染浓度超标10～30倍时,PAC吸附DEHP的最佳条件为:吸附时间120 min,PAC投加量为20～80 mg/L,PAC对DEHP的吸附过程符合Henry等温式。     

紫外分光光度法测定饮用纯净水中邻苯二甲酸二己酯含量

目的：为建立饮用纯净水中的邻苯二甲酸二己酯含量的测定方法。方法：利用正己烷萃取饮用纯净水中的邻苯二甲酸二己酯,氮吹并用甲醇定容,建立紫外分光光度法对其进行含量测定,并对条件进行优化。结果：方法标准曲线方程为y＝1.5347x＋0.0266,线性相关系数为0.9970,该方法连续测定精密度为0.644%,重现性相对标准偏差为0.5742%,加标回收率为88.89%～97.73%。结论：建立紫外分光光度法测定瓶装饮用纯净水中邻苯二甲酸二己酯的方法,该方法简单快速,结果令人满意。     

基于尿苷二磷酸葡萄糖醛酸转移酶1解毒通路探讨枸杞汁对邻苯二甲酸二(2-乙基己基)酯代谢的干预作用

目的:通过大鼠毒性干预实验观察枸杞汁对邻苯二甲酸二(2-乙基己基)酯(di-(2-ethylhexyl)phthalate,DEHP)染毒大鼠肝脏中尿苷二磷酸葡萄糖醛酸转移酶1(uridine diphosphate glucuronosyltransferase 1,UGT1)活性及代谢解毒的影响,探讨枸杞汁对DEHP代谢的干预效果。方法:60只雄性大鼠随机分为对照组、DEHP组和枸杞汁干预组,每组20只,DEHP组和干预组在DEHP一次染毒(3 000 mg/kg mb)后连续7 d分别灌胃生理盐水和枸杞汁,对照组则给予同等体积的芝麻油或生理盐水,期间每天收集大鼠24 h尿液。在染毒1、3、5、7 d后各组分别随机处死5只。采用试剂盒检测肝脏UGT1的活力,高效液相色谱法检测血清中的邻苯二甲酸单(2-乙基己基)酯(mono-(2-ethylhexyl)phthalate,MEHP)以及尿液MEHP和邻苯二甲酸(phthalic acid,PA)含量。结果:枸杞汁干预组大鼠第5天UGT1活性显著高于DEHP组和对照组(P0.05),且相对于DEHP组血清中MEHP含量减少而尿液中MEHP和PA含量增加。结论:枸杞汁可能通过提高UGT1活力促进了DEHP的代谢与排泄,发挥了解毒效应,将来可能作为一种预防或对抗邻苯二甲酸酯类物质或其他有毒化学物潜在危害的保健药材或功能食品用于人群的健康防护。     

食品塑料袋中DEHP气相色谱检测方法的建立

DEHP是塑料中常用的增塑剂之一,直接与内装高脂食品接触时,能够从塑料中迁移到内装食品中,造成内装食品的污染。DEHP对人体系统有不良影响,具有致畸、致癌的作用。本实验对各种材质(PVC、PE、PP、PS等)的食品塑料袋中DEHP的测定进行了较为系统的研究,采用气相色谱法,FID检测器,对DEHP进行测定。本方法检出限为3.38×10-3mg/kg,加标回收率为90.7%～105.1%,能够满足各种材质食品塑料袋中低浓度至高浓度DEHP含量测定的需要。     

PVC制品中增塑剂DEHP含量的测定

建立了荧光光度法间接测定聚氯乙烯(PVC)制品中邻苯二甲酸二(2-乙基己酯)(DEHP)含量的方法。PVC制品中的DEHP经超声提取后,碱性水解生成邻苯二甲酸钠,将其置于pH值为7.6的磷酸盐缓冲溶液中,同Fenton反应产生的羟基自由基(?OH)反应,生成具有荧光的羟基邻苯二甲酸钠,测定其荧光强度可求出DEHP的含量。DEHP浓度在4.28×10-2～2.14mg/ml范围内与荧光强度呈线性关系,相关系数为0.9954。本测定方法操作简便,具有较高的灵敏度和准确度。     

PVC一次性使用输液器中可沥滤物研究

通过模拟临床使用PVC一次性输液器的输注,对一次性使用输液器中可沥滤物进行了分析。建立了增塑剂邻苯二甲酸二(2-乙基己基)酯(DEHP)的高效液相分析方法,粘合剂环己酮的顶空气相色谱分析方法及金属元素(Cr、Cu、Cd、Sn、Ba、Pb)的电感耦合等离子体质谱分析方法。结果表明DEHP在3.674~104.970μg/mL范围内线性关系良好(r=0.9995),平均回收率为99.1%(n=9,RSD=1.7%);环己酮在0.5100~10.201μg/mL浓度范围内线性关系良好(r=0.9995),平均回收率为101.1%(n=9,RSD=2.4%);六种金属元素在0~100μg/L浓度范围内线性关系良好(r=0.9999),平均回收率在97.8%~110.6%(n=9,RSD≤2.8%)。本文建立的方法准确、灵敏,适用于PVC输液器中DEHP、环己酮和金属元素的溶出进行测定,为标准完善、质量监督及相关风险评价提供了参考依据。